This might make you feel old, but Nirvana's Nevermind turns 20 this September. As Spin reports, Universal will celebrate that anniversary by releasing a box set of the album on September 19, which will include a whole ton of extra material.The box will consist of four CDs and one DVD, including rarities, B-sides, unreleased recordings, and BBC radio appearances. The DVD will feature an entire unreleased live show. According to Spin, those BBC appearances are "most likely from four in-studio sessions recorded between 1989 and 1991," including sessions for John Peel and Mark Goodier. Spin also reports that Universal will continue to celebrate the Nevermind anniversary with "various events and releases" throughout the year.